


My Firstborn In Exchange For Power?! (A Tale of Unlikely Romance!)

by Snowy_Rain



Category: Harry Potter - J. K. Rowling
Genre: "In exchange for ur firstborn i shall grant u incredible power", Attempt at Humor, Awkward Romance, Awkward Sexual Tension, Crack, Demon Deals, Demon Summoning, Demon Voldemort (Harry Potter), Demon/Human Relationships, Horny Harry Potter, I can't believe this is a tag, I swear it, Implied Mpreg, Just assume everything is awkward, M/M, Memes, This Is Not Cringe, WHY is it a tag??, its "in exchange for ur firstborn i'll give u torturous training", no. no sir., the title is a joke
Language: English
Status: Completed
Published: 2020-07-18
Updated: 2020-07-18
Packaged: 2021-03-04 23:54:33
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,136
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25355080
Author URL: https://archiveofourown.org/users/Snowy_Rain/pseuds/Snowy_Rain
Summary: Harry Potter, sixteen-year-old child hero, uses desperate measures to win the war against Grindelwald. It's just the cherry on top that the demon he summoned looks like a Calvin Klein model. (And no, heisn'tgoing to bang the demon. What do you mean that's a lie? He willsueyou.)
Relationships: Harry Potter/Voldemort
Comments: 31
Kudos: 383





	My Firstborn In Exchange For Power?! (A Tale of Unlikely Romance!)

**Author's Note:**

  * For [ZypherT](https://archiveofourown.org/users/ZypherT/gifts).



> This is a gift for my close friend crea! (Honey, COME GET UR CRACK <333)

The day that the only copy of  _ Magick Moste Evile  _ Hogwarts had was stolen, the sky wept drops of arsenic, the clouds roared with the groans of the damned, lightning struck the towers of the castle, and Harry Potter ran under his invisibility cloak.

In his defense, his sense of drama had yet to be refined, and all he knew how to do was use the gloomy environment to his advantage - just like a typical teenager unable to bend the elements to their own dramatics. A dramatic  _ adult,  _ however, would have been perfectly capable of injecting a sense of utmost significance to this moment without the extra props.

Anyway -  _ Magick Moste Evile  _ was an invaluable resource and reference material for Harry Potter right now. As most mages didn’t have a lick of common sense  _ (and they were rather aggressively fake-Christian or plain old atheist) (and maybe with the added effect of not having read a Bible or any religious text, most times)  _ they either had no knowledge about demon summoning or believed it to be hogwash. But Harry Potter was a desperate teenager with a healthy appreciation for the dramatics, so he filched the only copy Hogwarts had of demon summoning rituals and ran to the  _ Forbidden Forest, _ because it was the only place dramatic enough to hold a demon summoning ritual. __

The book didn’t even have any anti-theft charms on its person. Harry Potter had been lucky enough that Madam Pince was a non-believer as well, also being more concerned about the safety of the books in more immediate reach of schoolchildren. The woman had her priorities straight. Good going.

So despite the rain that was blurring his glasses and thus his sight, as well as making  _ Magick Moste Evile  _ a bit wetter than normal, Harry Potter situated himself nearby a flowing creek and began chanting, tracking the shown diagram on the damp earth with his foot as he went in a circle. When he finished, he read the next instructions and spoke.

“Lord of fire and destruction,” he said, “I wish for a favor and I’m willing to pay for it. Please, grant me an audience!”

And because it was dumb and dramatic, he threw in a few words in Latin, those that meant things such as  _ fire, brimstone,  _ and  _ blood.  _ As mentioned before - his sense of drama needed a polish. 

However, because this was magic and because Harry Potter was the personification of luck, the demon  _ Voldemort  _ heard his plea and wondered what his deal was, to request an audience with a demon as a mage.

Voldemort materialized before him and Harry screamed in a pitch reminiscent of a woman seeing a rat. Or Ron seeing a spider the size of his pinky finger’s tip. Take your pick.

“Oh dear,” Voldemort spoke. “I didn’t realise you were a schoolboy. My bad.”

Harry stood shell-shocked and unbelievably turned on. He hadn’t thought that his stupid plan would work, and he also hadn’t foreseen that his summoned demon would look like a Calvin Klein model. Not that he had seen a lot of Calvin Klein models, but the demon  _ looked  _ like the prime target of a modeling agency.

“Um,” he mumbled. “No problem? Anyways, I had-”

“Yes, yes, I know,” Voldemort cut in, stepping out of the circle and taking out a stack of documents. Harry’s eyes locked onto the muscles on his thighs, flexing with each small movement. He wanted to get  _ murdered  _ by those thighs. There was truly no end to teenage hormones.

“A deal requires a soul, traditionally,” Voldemort continued, taking out a few of the papers from the stack. “But I don’t take the souls of minors. It’s unethical.”

Harry gaped and said, “What am I going to give you then?”

“Your firstborn, perhaps?” Voldemort shrugged. “I don’t particularly care, but your firstborn would be a good sacrifice. If you aren’t amenable to that, I could also take the soul of your enemy - but you would need to bring them here and call me at a later date-”

“You mean I could have sacrificed  _ Grindelwald  _ to you?” Harry exclaimed, aghast.

“Pay attention.  _ Yes.  _ Theoretically, you could have. However, there are many semantics to this exchange. If Grindelwald has Horcruxes, I won’t be able to collect his soul, which would also nullify our deal. Anyway-” Voldemort waved a hand. “What was your wish?”

“To- To defeat Grindelwald.”

“Oh.” Voldemort sounded awkward now, “Well, in that case, I  _ do  _ require your firstborn. And I also cannot kill him in your stead.”

_ “Why?” _

“As I said,  _ semantics.  _ Being a demon has a lot of fine print. It’s a pity they don’t tell you that when they extend the offer.”

And so they stood there in the middle of the forest, under the drizzle, one half-naked with only a decorated loincloth to cover his manly bits, while the other was a sixteen year old school boy with no sense of tasteful drama.

“Um,” Harry’s voice pierced the silence. “So you wanna go get some grub?”

_ “Yes _ please.”

***

Hot, nearly naked demon Voldemort and child hero Harry Potter were dining in the kitchens at dawn. Though the two were quite respected and prominent figures in their own circles, they became incoherent and lame fools around each other, not knowing how to act.

“I once took the left leg of the summoner when I was summoned, during one of my first jobs,” Voldemort rambled. Since the two idiots didn’t know how to communicate with each other quite yet, they took to talking about their pasts. “Admittedly, I didn't know what to do at that time, merely that it was Necromancy gone wrong. And even worse was that the summoner was a child younger than you are, and I also accidentally took the child’s sibling’s whole body because of my mishandling of the summoning fumes. Needless to say, that was a nightmare. But it was resolved somehow.”

Harry whistled, half-listening while he ogled Voldemort’s delicious arms. “Wow.”

“Indeed. In the end, I had the opportunity to return the body through another summoning, in exchange for the summoner’s power to reach out to the demonic realm. I’m rather glad that I haven’t had such errors in centuries.”

“So, about the matter with my firstborn,” Harry started, because he didn’t know how to close one topic and open another, “am I going to get pregnant now?”

Voldemort paused, looking oddly pensive. “...Do you want to?”

Now Harry looked pensive as well. “I don’t know actually.”

“Well, there is always that option. But no - generally, your firstborn qualifies even if it’s born from the womb of someone who isn’t the summoner. As long as you are one of the parents, I see no issue.”

“That’s… a relief. Are you full now?”

“Oh, yes.” The demon dabbed at the leftover lamb juice on his lips with a napkin, drawing Harry’s horny attention. Was it possible to get turned on by something so utilitarian like that? Harry was the living proof that it  _ was,  _ indeed, possible. One hundred percent. Harry would bang him, ten out of ten. If Voldemort had been human, Harry would have gotten on that dick a million years ago - but the sad truth was Harry wasn’t attracted to monster dongs, so he didn’t know if he would enjoy that dick.

_ No thirsting after your demon,  _ Harry tried to tell his lizard brain.  _ You can’t fuck demons, they aren’t your species! You are attracted to human dongs! You have a girlfriend! _

_ Ha ha, Voldemort hot demon, dick go brrr,  _ his lizard brain responded, laughing in his face. Harry clenched his fist in defeat. It had a point,  _ dammit. _

“I have to draw up the contract,” Voldemort told him. “Then we can start with the training.”

All of Harry’s thoughts about banging the demon paused.

“...Training?” he asked, fearing for his life at the look Voldemort gave him.

In any other context - _any_ other context - that gaze would have been sexy. It would have been classified as _bedroom eyes._ It would have sent the blood _rushing_ to his nether regions. However, this wasn’t that context.

Voldemort grinned, a mouth full of beautiful yet sharp teeth. “Yes.  _ Training.” _

Harry needed to write his will. Maybe he could bang Voldemort in the afterlife? That sounded doable.

***

In the next few months, Harry understood  _ why  _ Voldemort was a demon. The man was such a hardass professor that within five minutes of  _ The Training,  _ Harry swore that he would prefer death over this.

“Oh?” the demon in the guise of a human being asked. “We aren’t done yet, Harry. You won’t be free of me until you are able to withstand  _ a quarter  _ of my power. Stop crawling on the floor like a maggot and  _ take it like a man.” _

Harry would rather try his chances with the monster dong, thank you very much.

The months of training, however, showed its results visibly. Harry now looked more like a normal adolescent than a waifish, elfin child with a baby face. He  _ did  _ have his baby face still, but it was now framed by a manlier, stockier body able to withstand a fucking  _ demon.  _ There weren’t many wizards able to claim that. On top of that, he now had the magical stamina of a duelling champion - namely,  _ Flitwick,  _ who was a fucking powerhouse in that diminutive body - and the spell repertoire of a bona fide Chosen One, primed by the Gods themselves to fight  _ Evil _ . Capitalized.

Voldemort smacked him on the back of his head to keep him from getting a big head. 

***

When Hogwarts was invaded by Grindelwald’s men, they were taken by surprise by the extremely massive (positively humongous, absolutely every-word-in-the-thesaurus-that-meant-“big”) explosion of power that wrecked their ward-breaker artifact.

“My Lord!” Tortus Hallewin exclaimed, pointing at the building energy on the grounds. “Opposition ahead!”

“Yes, I can  _ see  _ it, you fool!”

The men, though they were clever and cruel, were as arrogant as they come. Because of this, they thought that they could win against this unexpected addition.

Well… They didn’t. Harry Potter descended upon them with the fury of a thousand souls that cried for revenge, and neither Grindelwald nor his Acolytes survived the resulting magical bombing.

“I kind of thought this would be harder?” Harry asked Voldemort, who shrugged in response.

“I didn’t know they would be so weak. Well done, my dear pupil. Training is over.”

“Training is over,” Harry repeated, sinking to his knees. In retrospect, this announcement had lightened his spirits more than decimating Grindelwald had. He faced the bright blue sky, raised his hands up, and shouted, “Training is…  _ oooooveeeeeeeeeeeeeeerrrr!!!” _

“For the love of seven circles _ \- get up.  _ You’re bringing shame to my name.”

Harry got up and stood before Voldemort. You know - all hard, sweaty muscle? Check. Tiny-ass loincloth covering absolutely  _ delicious  _ parts? Check. Intense red gaze? Yep. Long eye lashes, shapely eyebrows, a godlike nose?  _ Yeah, yes please.  _ Mussed up and ready-for-a-tumble hair?

_ Check.  _ And suddenly, Harry found that he had no qualms about demon dicks. They could, like, do it with his mouth maybe? That worked.

“So you wanna kiss or stuff?” he asked, because he was awkward and not suave at all. He wasn’t  _ actually  _ protagonist material.

Voldemort hummed. And because he was also awkward and lame, he said, “I have sharp teeth.”

“Oh. Cool. So, you like the broom cupboard or…?”

Voldemort sighed. “Yeah, broom cupboard works I guess.”

And they ran to the closest broom cupboard to snog and do unspeakable things to each other. As a bonus point, Harry also discovered that Voldemort’s dick was perfectly fine, thank you very much.

***

“Wait a moment,” Harry spoke, eyes snapping wide open. He was in bed with his brand new husband Voldemort the Demon Lord, nearly three weeks pregnant. “I fulfilled the contract.”

Voldemort groaned as the sleepy sensations left him. Harry’s conspiratorial voice had woken him up from his dozing. “What now?”

“I’m fucking  _ pregnant,”  _ he continued, furiously whispering. “But you’re gonna be the father? So the child is already yours! That- Merlin’s fucking  _ dick,  _ I found a _ loophole.” _

Voldemort and Harry lay side by side in silence, as awkward as they were during their first meeting.

“I want to say  _ you know too much  _ but you’re my husband, so,” Voldemort spoke, but didn’t say the rest. Harry mumbled about tricky demon bastards under his breath and kicked his husband in the shins with his cold feet. Voldemort made a mildly surprised noise.

_ It’s probably better that I don’t tell him I eat those as snacks,  _ Voldemort thought.  _ Yes. That would be for the best. _

Meanwhile, Harry’s mind was busy with what other loopholes he could find. Silly Harry. Though he was nearly twenty-five, his sense of dramatics still lacked polish. Good thing Voldemort was there to accompany him through it.

**Author's Note:**

> :))))


End file.
